DESCRIPTION: (Applicant's Description) This application, to participate in the Cooperative Family Registry of Colon Cancer, capitalizes on the applicant's experience in conducting family studies of colorectal cancer (CRC) in Hawaii, on the unique access to under-served and understudied ethnic minorities at high and low risks for CRC, as well as on characteristics of Hawaii's population which make it eminently suitable for genetic epidemiology (remoteness, stability, large pedigrees, population registries, good compliance). This new initiative also builds on several NIH-supported, population-based research projects on environmental and genetic factors and attitudes toward genetic testing for CRC. The aims of this application are: 1) to establish a family registry and bio-repository for high-risk families in Hawaii and to contribute data and specimens for about 130 new intermediate and high risk families for CRC (an additional 140 families from the current family study will also be contributed after publication of results); 2) to develop and pilot test protocols using the Cooperative Family Registry: a) to describe the mutational spectra and clinical characteristics of known hereditary syndromes of CRC in ethnic populations, b) to assess the penetrance of relevant mutations in individuals of various ethnic backgrounds, c) to conduct intervention studies among high risk individuals with regard to early detection, diet and exercise, d) to study psychological issues related to high familial risk and predictive genetic testing. All new incident cases of CRC on the island Oahu for 1997-2000 (n=2,280) will be screened for family history of CRC among first degree relatives. Patients with one or more first degree relatives with CRC and their relatives will be included in the registry. Selected second degree relatives will also be included for some multicase families. Data on personal and familial history of cancer and on environmental risk factors will be collected from each participant, as well as a blood sample and tumor blocks. Selected long-term benefits of this research include data on the molecular genetic epidemiology of CRC, as well as on the acceptability of predictive genetic testing for CRC in ethnic groups, including Native Hawaiians and Japanese, that are difficult to study anywhere else in the United States and the invaluable research insights that may result from cross-ethnic and cross-cultural comparisons.